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THE FUEL SYSTEM is a simple state‐of‐the‐art system which is designed to minimise system maintenance and provide a very high probability of mission success. It requires no fuel management or manipulation of system controls during a normal mission. It is designed to use MIL‐J‐5624G, grades JP‐4 and JP‐5 turbine fuel.

Determining the variation law of the oxygen concentration in the ullage space of the fuel tank is the key to the design of the inert system. Among various factors affecting the oxygen concentration in the ullage space of the fuel tank, the temperature difference between day and night shows particular importance while relevant analysis and calculation are scarce.

This study establishes a theoretical simulation model of the central wing fuel tank of an aircraft according to the relevant provisions of day-night temperature variation in FAR25 airworthiness regulations, verifies the model with the existing experimental data and discusses the corresponding relationship between the oxygen concentration in the ullage space of the fuel tank and the day-night temperature difference. The influence of day and night temperature difference, fuel type, fuel load rate, initial oxygen concentration, dissolved oxygen evolution and other factors on the oxygen concentration in the ullage space of the fuel tank were analyzed, and the limit of initial oxygen concentration of the fuel tank before the shutdown at night meeting the requirements of the airworthiness provisions was proposed.

The results show that the temperature difference between day and night, fuel load rate, initial oxygen concentration and other factors have different effects on the oxygen concentration in the ullage space of fuel tank. The initial oxygen concentration limit before shutdown shall be 2% below the 12% oxygen concentration stipulated by FAA.

The research results in this paper will be of good reference value to the design of the inert system and the calculation of the flammability exposure evaluation time. This paper aims to be good reference of the design of the inert system and the calculation of the flammability exposure evaluation time.

The research results of this paper can provide practical guidance for the current civil airworthiness certification work.

Explains the fuel system of the Boeing 777‐200 aircraft. Looks at the system’s features, the fuel feed, the fuel jettison and the flight deck displays in terms of the fuel system.

Discusses the requirements for refuelling civil airliners, particularly under pressure refuelling. Analyses the problems that can arise and demonstrates how advancing technology has changed the appearance and efficiency of many components, particularly with reference to the control panel. Describes in detail the workings of a typical system; aspects of control of fuel quantity in refuelling; refuel control panels; and fuel gauges, with particular reference to the Boeing 777.

THE need to carry sufficient fuel in the smallest possible space and with the lowest possible weight dictated the use of integral fuel tanks in both the wing and the fuselage, despite the recognised difficulty of scaling tanks of conventional aircraft construction with complex shapes.

PHOENICS, a general 3‐D Navier‐Stokes computer program, was used to simulate cooling and freezing of jet fuel stored in airplane fuel tanks. A 3‐D analysis is required for fuel tanks of arbitrary geometry exposed to time dependent and nonuniform boundary temperatures. The work reported in this paper concentrated on 2‐D simulations of fuel cooling and freezing in a wing tank and external (pylon) tanks as a step toward the 3‐D analysis. Significant progress has been made on obtaining plausible solutions over the entire range of conditions considered. The same model, with appropriate changes for fuel properties, could also be used to predict fuel heating in airplane fuel tanks during supersonic flight conditions.

THE considerable difficulties encountered in designing a test rig which would allow of unbroken fuel supply from tanks whose attitude was being changed continuously was successfully overcome.

This paper aims to present a knowledge-based fuel system, implementation and application, oriented towards its use in aircraft conceptual design.

Methodology and software tools oriented to knowledge-based engineering applications (MOKA) is used as a foundation for the implementation and integration of fuel systems.

Including fuel systems earlier in the design process creates an opportunity to optimize it and obtain better solutions by allocating suitable locations in an aircraft, thereby reflecting on the centre of gravity of the aircraft.

All geometries are symbolic, representing a space allocation inside the aircraft for the fuel system. A realistic representation of the real components could be realized in detail design.

Fuel weight is a significant part of take-off weight and decisive in aircraft sizing and range estimations. The three-dimensional geometry provides a better estimation of the volume that is available to allocate the necessary entities. It also provides fast measures for weight and balance, fuel capacity, relative tank positions and a first estimation of piping length.

Fuel systems appear early in the design process, as they are involved in several first estimations. By using a knowledge-based engineering approach, several alternatives can be visualized and estimated in the conceptual design process. Furthermore, using the weights and centre of gravity at different angles of pitch and roll of each fuel tank, the aircraft could be optimized for handling qualities by using automatically generated system simulation models.

Cooldown of fuel inside a horizontal cylinder (i.d. approximately equal to that of a pylon tank) was modelled with a mixture of 50% glycerine and 50% water (Ti = 65°C). Safety considerations and poor optical qualities at low temperatures precluded fuel from being used in these experiments. The test was started by suddenly imposing a nominal 10°C external temperature field (flowing tap water) on the aluminium skin. Fluid velocities and temperatures were measured during the transient near the mid‐length plane of the cylinder, where end effects were reduced. Therefore, the physical situation at this plane was considered amenable to a 2‐D analysis. Tests were conducted with a full partially full tank and included tests with the tank tilted 10° from the horizontal to determine axial convection effects; this angle approximates an angle of attack during cruise. Tilting the tank produced temperatures at the elevated end which were significantly higher than those at the lowered end, especially for the bottom ½ of the tank where the ΔT between ends was as high as 5°C 30 minutes after the start of test.